The present invention relates to a new and improved construction of a selvedge cutting device or cutter for a weaving machine or loom, which serves to cut the selvedge from the fundamental weave or foundation fabric prior to winding-up the same, and is of the type containing a cutter tool guided in the cutting lane or alley at the fabric selvedge.
It is generally known in this technology that, during the fabrication of certain fabrics, it is necessary to cut the so-called selvedge from the fundamental weave or foundation fabric, since the selvedge, during winding-up of the fabric tends to markedly bulge, and thus, can distort the fabric. Consequently, at the warp there is provided, near to the selvedge or edge of the fabric, an intermediate space constituting a so-called cutting alley or lane for accommodating a selvedge cutter which continuously severs the weft or filling threads in such cutting alley or lane.
An appreciable problem which prevails when using this technique resides, however, in the fact that the position of the cutting alley can appreciably vary, for instance during standstill of the weaving machine or due to climatic conditions. When this occurs it is known that such can cause relatively large fluctuations in the fabric width.
To take into account this phenomenon the selvedge cutter must be capable of following such deviations. Heretofore this could not be satisfactorily accomplished with the prior art selvedge cutters.
There is generally known to the art a selvedge cutter, wherein a stationary cutter is oriented or positioned in the cutting alley or lane by means of a leading feeler wheel or roll. However, with this arrangement the cutter is pivotably adjusted in the fabric plane, so that the danger exists that the cutter will cut into the fundamental weave. Apart from the foregoing shortcoming this arrangement cannot be used for denser fabrics, since in this case the feeler wheel does not stay in its track.
With a similar arrangement known in this technology the cutter is additionally driven for obtaining a sawtooth movement. While such increases the service life of the cutter and improves upon the cutting operation, nonetheless there is required in this case an extremely complicated cutter construction, so that the drive can follow the deflection movements of the cutter along the cutting alley. Apart from the foregoing, in this case there also is present, and for the same reasons, the danger of cutting into the fundamental weave or foundation fabric.
Proposals which have been advanced for maintaining the cutter in the center of the cutting lane or alley through the use of optical control means, have failed because of the attendant high technical expenditure which is required for this purpose, and furthermore, cannot be used at all in those instances where the fabric selvedge serving as the guide edge is frayed.
Additionally, what is disadvantageous with all of the heretofore known arrangements is that the fabric is continuously pressed against the cutter. Consequently, there is hindered the adjustment movements of the cutter and there is accelerated the wear at the cutting edge. While this drawback could be avoided with scissors, the control thereof is difficult to realize, however, owing to the required drive.